Resilient midsoles for footwear

ABSTRACT

A midsole for footwear, and footwear that incorporates the midsole, where the midsole includes a resilient core disposed between an upper housing and a lower housing, and including and a sidewall assembly extending from the perimeter of the upper housing to the perimeter of the lower housing, the sidewall assembly being configured to accommodate a compression of the midsole.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority from U.S. Provisional Patent Application Ser. No. 62/099,130, filed Dec. 31, 2014, which is hereby incorporated by reference in its entirety.

INTRODUCTION

Highly compressible materials are typically not used in the midsoles of work boots, due to the relative vulnerability of such materials to environmental hazards such as debris or workplace chemicals. By at least substantially enclosing such highly compressible materials, a highly resilient midsole can be constructed that confers onto footwear enhanced compressibility, shock absorption, and energy return making them more comfortable and decreasing user fatigue.

SUMMARY

Disclosed herein are examples of footwear and footwear systems and methods. In one example, footwear having compressible midsoles are disclosed. The midsoles may include an upper housing, a lower housing, and a sidewall assembly extending from the upper housing to the lower housing, and a resilient core disposed between the upper housing and the lower housing and within the sidewall assembly. The sidewall assembly may be configured to accommodate the compression of the midsole.

Features, functions, and advantages may be achieved independently in various embodiments of the present disclosure, or may be combined in yet other embodiments, further details of which can be seen with reference to the following description and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of an example of footwear of the present disclosure having a compressible midsole, with arrows showing the direction of compression.

FIG. 2 is a cross-section view of an exemplary midsole of the present disclosure without and with vertical compression applied to the midsole.

FIG. 3 is a cross-section view of another exemplary midsole of the present disclosure.

FIG. 4 is a cross-section view of yet another exemplary midsole of the present disclosure that incorporates a plurality of hollows in its resilient core.

FIG. 5 is a side view of an example of footwear of the present disclosure showing the compressible midsole compressing and decompressing as a step is taken using the footwear.

FIG. 6 is a cross-sectional view of an exemplary midsole of the present disclosure having an upper sidewall that is disposed outside a corresponding portion of lower sidewall.

FIG. 7 is a cross-sectional view of an exemplary midsole of the present disclosure in which a portion of an upper sidewall is disposed within a complementary gap or slot in a lower sidewall.

FIG. 8 is a cross-sectional view of an exemplary midsole of the present disclosure having a portion of an upper sidewall that is disposed within a corresponding portion of a lower sidewall 30.

FIG. 9 is a cross-sectional view of an exemplary midsole of the present disclosure having a lower sidewall configured to slide along an outer portion of an upper housing.

FIG. 10 is a cross-sectional view of an exemplary midsole of the present disclosure having an upper sidewall configured to slide along an outer portion of a lower housing.

FIG. 11 is a cross-sectional view of an exemplary midsole of the present disclosure having a unitary sidewall that incorporates a pleat.

FIG. 12 is a cross-sectional view of an exemplary midsole of the present disclosure having a unitary sidewall that incorporates a pleat.

DETAILED DESCRIPTION Overview

Various embodiments of shoes having enclosed resilient midsoles are described below and illustrated in the associated drawings. Unless otherwise specified, an embodiment and/or its various components may contain at least one of the structure, components, functionality, and/or variations described and/or illustrated herein. Furthermore, the structures, components, functionalities, and/or variations described and/or illustrated herein in connection with the present teachings may be included in other embodiments. The following description of various embodiments is merely illustrative in nature and is in no way intended to limit the disclosure, its application, or uses. Additionally, the advantages provided by the embodiments, as described below, are illustrative in nature and not all embodiments provide the same advantages or the same degree of advantages.

Disclosed herein are footwear having enclosed resilient midsoles. In some embodiments, the midsole may include an upper and lower sidewall configured to telescope under compression. In some embodiments, a sidewall of the midsole may include one or more pleats or corrugations that permit the midsole to telescope under compression.

FIG. 1 shows an example of footwear 10 of the present disclosure. The footwear may include an upper 12, an outsole 14, and a midsole 16 disposed between the upper 12 and the outsole 14. Upper 12 may cover any suitable portion of a user's foot. For example, the upper in FIG. 1 has a high cut (or high top) that may be designed to extend above a user's ankle bone. Although upper 12 is shown as having a high cut, upper 12 may have a low cut (or low top) that does not extend above a user's ankle bone or may have any suitable cut that covers any suitable portion of a user's foot.

The footwear of the present disclosure may include any suitable outsole. Outsole 14 may extend at least substantially the entire length of the footwear and may include a plurality of projections and/or recesses configured to improve traction. The projections may be substantial, for example in the case of a work boot or a hiking boot, or they may be minimal, as in the case of a running shoe or court shoe. The outsole may wrap around at least a portion of the toe of the footwear, or a portion of the heel of the footwear, or both.

Midsole 16 may be disposed between upper 12 and outsole 14. As shown in cross-section in FIGS. 2 and 3, midsole 16 may include an upper housing 18 that may define an interface between the midsole 16 and the upper 12, and a lower housing 20 that may define an interface between the midsole 16 and the outsole 14. The upper housing 18 and lower housing 20 may be composed of any suitable material, which may be the same or different. In one example, the upper housing 18 and lower housing 20 may be formulated from a suitable plastic, such as a thermoplastic or thermoset plastic. In particular, one or both of the upper housing 18 and lower housing 20 may include thermoplastic polyurethane (TPU) or ethylene-vinyl acetate (EVA).

Midsole 16 may further include a sidewall assembly 21, where the sidewall assembly 21 connects to both the upper housing 18 and the lower housing 20 along their respective perimeters, and considered in combination with the upper housing 18 and lower housing 20 the sidewall assembly defines a core chamber 22 that may house a resilient core 24. The resilient core may be attached to (and/or coupled to and/or proximate) one or both of the upper housing 18 and lower housing 20, and may occupy a portion of or substantially all of the interior space of core chamber 22. Resilient core 24 may be composed of any suitably compressive and resilient material. That is, the resilient core 24 may be capable of some degree of compression in the vertical direction in response to compressive force exerted between the upper housing 18 and lower housing 20, and may also be capable of substantially returning to its original volume once the compressive force is removed.

The resilient core may include one or more of a plastic foam, a gel, or a resilient mechanical component such as a spring. Where the resilient core includes a spring, the spring may be a coil spring, or a flex spring, among others. The resilient core may have a homogeneous composition, as shown in FIG. 3 or may incorporate a plurality of zones having differing degrees of resilience. For example, a portion of the midsole disposed below the ball of a user's foot, or below the heel of a user's foot, may have a greater degree of resiliency than the remaining portions of the midsole. These areas of contrasting resilience may be created by using foams or gels of differing resilience, or by embedding contrasting materials in the resilient core. For example, a foam core may include inserts of resilient gel, or one or more embedded springs.

Where the resilient core is not homogeneous, the resilient core may incorporate one or more hollows 26 or interstices, as shown in FIG. 4, in order to help reduce the overall weight of the footwear, to increase the compressibility of the midsole, or both. When such hollows are present in the midsole, the hollows may have any suitable shapes, which may be the same or different, and which may include circular, triangular, rectangular, and/or any suitable curvilinear and/or rectilinear shapes, among others. Additionally, hollows 26 may have any suitable size, which may be the same or different, provided that they are not so large as to substantially compromise the resiliency of resilient core 24 itself.

In order for the capacity for compressibility of core 24 to be more fully utilized, the midsole 16 may be constructed to offer decreased resistance to compression, while still offering protection to the resilient core 24 from the environment. In this way the resilient core 24 may be compressed and decompressed to its maximum capacity, providing greater comfort and enhanced energy return to the footwear user with each step, as shown in FIG. 5.

The sidewall assembly 21 may therefore include an upper sidewall 28 that may be connected to upper housing 18 and a lower sidewall 30 that may be connected to lower housing 20, where the upper and lower sidewalls are configured to telescope upon compression of midsole 16.

For example, as shown in FIG. 6, a portion of upper sidewall 28 may be disposed outside a corresponding portion of lower sidewall 30, such that upon compression of resilient core 24 the inner portion can telescope within the outer portion, and thereby offer little or no resistance to the compression of core 24. Alternatively, as shown in FIG. 7, a portion of upper sidewall 28 may be disposed within a complementary gap or slot 31 in the lower sidewall 30. In yet another alternative embodiment, as shown in FIG. 8, a portion of upper sidewall 28 may be disposed within a corresponding portion of lower sidewall 30, so that the sidewall assembly 21 is capable of telescopic compression, permitting maximal compression of resilient core 24.

Alternatively, as shown in FIG. 9, lower sidewall 30 may be configured to slide along an outer portion of upper housing 18, similarly permitting the midsole to telescope upon compression. Similarly, upper sidewall 28 may be configured to slide along an outer portion of lower housing 20, as shown in FIG. 10.

Configurations of midsole 16 that feature an upper and inner telescoping portion of sidewall assembly 21 may also create a greater risk for dirt and/or debris to enter the midsole via the interface between the upper and lower sidewalls, potentially shortening the life of the footwear. To prevent this possibility, sidewall assembly 21 may incorporate a unitary sidewall 32 that incorporates one or more pleats 34 or corrugations that are configured to accommodate the telescoping movement of the sidewall assembly, as shown in FIGS. 11 and 12 without also creating an opening to the environment that may admit outside contaminants.

Also as shown in FIGS. 11 and 12, in one aspect of the disclosed midsole, the lower housing 20 may be absent, such that resilient core 24 connects directly to outsole 14.

As the resiliency of midsole 16 may be primarily due to the resiliency of core 24, and as sidewall assembly 21 may be configured to allow core 24 to undergo compression freely, the sidewall assembly may incorporate materials that are less resilient than core 24. For example, the upper and lower sidewalls may include more rigid thermoplastics and thermoset plastics, such as TPU and/or EVA. In one aspect of the disclosure, a portion of the sidewall assembly may include a metal or metal alloy, thereby providing enhanced rigidity and toughness. Such a metal-containing sidewall assembly may be particularly advantageous for a work boot intended for use in particularly punishing environments, such as logging or heavy manufacturing.

Midsoles according to the present disclosure permit foam or mechanical springs to be used throughout the entire midsole, while also maintaining the exterior durability and stability of the footwear in which it is incorporated. The construction of the midsole permits it to be compressed and decompressed to its maximal capacity, compared to more conventional midsole configurations having embedded compression materials. The resulting footwear may offer greater energy return with each step.

Although the present invention has been shown and described with reference to the foregoing operational principles and preferred embodiments, it will be apparent to those skilled in the art that various changes in form and detail may be made without departing from the spirit and scope of the invention. The present invention is intended to embrace all such alternatives, modifications and variances that fall within the scope of the appended claims.

It is believed that the disclosure set forth above encompasses multiple distinct inventions with independent utility. While each of these inventions has been disclosed in its preferred form, the specific embodiments thereof as disclosed and illustrated herein are not to be considered in a limiting sense as numerous variations are possible. The subject matter of the inventions includes all novel and non-obvious combinations and subcombinations of the various elements, features, functions and/or properties disclosed herein. Similarly, where the claims recite “a” or “a first” element or the equivalent thereof, such claims should be understood to include incorporation of one or more such elements, neither requiring nor excluding two or more such elements.

Inventions embodied in various combinations and subcombinations of features, functions, elements, and/or properties may be claimed through presentation of new claims in a related application. Such new claims, whether they are directed to a different invention or directed to the same invention, whether different, broader, narrower or equal in scope to the original claims, are also regarded as included within the subject matter of the inventions of the present disclosure. 

What is claimed is:
 1. A midsole for footwear, the midsole comprising: an upper housing; a lower housing; a sidewall assembly that extends from a perimeter of the upper housing to a perimeter of the lower housing, wherein the sidewall assembly is configured to accommodate a compression of the midsole; and a resilient core disposed between the upper housing and the lower housing and within the sidewall assembly.
 2. The midsole of claim 1, wherein the resilient core is attached to at least one of the upper housing and lower housing.
 3. The midsole of claim 1, wherein the resilient core includes one or more of a resilient foam, a resilient gel, and a molded spring.
 4. The midsole of claim 1, wherein the resilient core includes one or more voids to enhance the compressibility of the core and/or to enhance the restoration ability of the core.
 5. The midsole of claim 1, wherein the resilient core is substantially homogeneous throughout the midsole.
 6. The midsole of claim 1, wherein the resilient core includes a plurality of zones, each zone having distinct compressibility characteristics.
 7. The midsole of claim 6, wherein each zone includes a resilient foam.
 8. The midsole of claim 1, wherein the sidewall assembly includes an upper sidewall connected to the upper housing and a lower sidewall connected to the lower housing, wherein the upper and lower sidewalls are configured to telescope upon compression of the midsole.
 9. The midsole of claim 8, wherein the lower sidewall is configured to telescope within the upper sidewall.
 10. The midsole of claim 8, wherein the upper sidewall and lower sidewall form a unitary structure that incorporates one or more pleats that accommodate the telescoping movement of the sidewalls.
 11. The midsole of claim 8, wherein the upper sidewall and lower sidewall are distinct structures.
 12. Footwear, comprising: a footwear upper; a footwear outsole; and a midsole disposed between the upper and the outsole, the midsole comprising: an upper housing; a lower housing; a sidewall assembly that extends from a perimeter of the upper housing to a perimeter of the lower housing, wherein the sidewall assembly is configured to accommodate a compression of the midsole; and a resilient core disposed between the upper housing and the lower housing and within the sidewall assembly.
 13. The footwear of claim 12, wherein the footwear is a work boot.
 14. The footwear of claim 12, wherein the resilient core includes one or more of a resilient foam, a resilient gel, and a molded spring.
 15. The footwear of claim 12, wherein the resilient core includes a resilient foam.
 16. The footwear of claim 12, wherein the resilient core includes one or more voids configured to enhance the compressibility of the core.
 17. The footwear of claim 12, wherein the sidewall assembly includes an upper sidewall connected to the upper housing and a lower sidewall connected to the lower housing, wherein the upper and lower sidewalls are configured to telescope upon compression of the midsole. 